Check out the synopsis for the penultimate episode of Supernatural‘s eighth season, titled “Clip Show,” below.

The official press release has the following information about the episode:

FAMILIAR FACES RETURN AS THE THIRD TRIAL NEARS — Sam (Jared Padalecki) and Dean (Jensen Ackles) reunite with Castiel (Misha Collins). Digging through the Men of Letters’ files, they stumble upon an undiscovered film which could be the key to the third trial. Metatron (guest star Curtis Armstrong) enlists Cass to mull over problems at home. Meanwhile, Crowley (guest star Mark Sheppard) digs into Sam and Dean’s past. Taylor Cole, Graham Wardle, and Cindy Busby also guest star. Thomas J. Wright directed the episode written by Andrew Dabb (#822).

We previously reported on Cole’s return as Sarah Blake, Sam’s love interest from episode 1×19 “Provenance.” We also learned that another character from earlier on in season 1 would also appear. Now we know who that is: Graham Wardle appeared in episode 1×02 “Wendigo” as Tommy Collins, a camper taken by a wendigo and rescued by the Winchesters.

The other part of the synopsis that we’re intrigued by is the appearance of Metatron, who Castiel described as an angel who acted as “the scribe of God. He took down dictation when creation was being formed,” which ended up on the tablets that only prophets can decipher. However, he disappeared after the tablets were completed.

We’ll be interested to see how all these pieces tie together in relation to the third and final trial for shutting the gates of Hell permanently.